Heterogeneous molecular Co–N–C catalysts for efficient electrochemical H2O2 synthesis?

Energy & Environmental Science Pub Date: 2022-11-29 DOI: 10.1039/D2EE02734H

Abstract

Sustainable hydrogen peroxide can be produced via the oxygen reduction reaction catalyzed by single-atom cobalt–nitrogen–carbon catalysts. However, the precise catalyst atomic structure tailoring remains difficult, limiting the a priori design and activity improvement. We address this limitation by constructing heterogeneous molecular catalysts from cobalt porphyrins adsorbed on a carbon nanotube substrate. Based on the explicit atomistic models, our first-principle calculation suggested that porphyrin β-substituents and the carbon substrate can synergistically modulate Co properties and catalytic activity. An octafluoro-substituted catalyst was predicted as optimal and further validated by experiments, exhibiting >94% H2O2 selectivity and a high turnover frequency of 3.51 per second at an overpotential of 200 millivolts in an acid electrolyte. It can reach a maximum H2O2 productivity of 10.76 molH2O2 gcat?1 h?1 in a two-electrode electrolyzer, delivering pure H2O2 solutions that can be used directly for water treatment and chemical production.

Graphical abstract: Heterogeneous molecular Co–N–C catalysts for efficient electrochemical H2O2 synthesis
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